The present invention relates to optical radiation measurement apparatus commonly known as a photometer or radiometer and, more particularly, to a novel high-sensitivity photometer/radiometer utilizing a single-pixel chargeinjection-device (CID) and associated circuitry, for sensing optical radiation magnitudes less than 10E-14 watts/cm.sup.2.
It is well known to provide optical radiation measurement apparatus utilizing a solid-state sensor, such as a silicon diode detector and the like, or a vacuum tube sensor, such as photomultiplier and the like. It is known that a silicon diode detector can measure irradiance levels as low as about 10E-9 watts/cm.sup.2, and that photomultiplier systems can measure irradiance levels as low as about 10E-12 watts/cm.sup.2. A photometer using prior sensors and having a sensitivity of this order is not only expensive and complex, but will still also have a minimum sensed irradiance level which is equivalent to about 3E+7 photons per second per square centimeter. This minimum level is about 7 orders of magnitude greater than the desired ultimate sensitivity of a photometric device, i.e. a sensitivity approaching 1 photon per second per square centimeter is highly desirable. Thus, in the photonics field, wherein precise measurement of optical radiation is of great importance, even a one orderof-magnitude increase of sensitivity over the common photomultiplier sensitivity level of 10E-12 watts/cm.sup.2 is not only significant, but highly desirable.